Revistas
Revista:
RAPID PROTOTYPING JOURNAL
ISSN:
1355-2546
Año:
2020
Vol.:
26
N°:
2
Págs.:
349 - 359
Purpose The purpose of this study is to explore a methodology for connecting microelectromechanical system sensors - i.e. inertial measurement unit (IMU) - to an Arduino-based microcontroller, using graphene-based conductive filament and flexible thermoplastic polyurethane (FTPU) filament and low-cost dual material extrusion technology. Design/methodology/approach A series of electrical tests were carried out to determine the maximum resistance the conductive paths may take to connect printed circuit boards (PCB). To select the most suitable printing material, three types of conductive filaments were examined. Then an experiment was carried out to find the best printing parameters in terms of printing speed, printing temperature and layer height to minimise resistivity. The size of the conductive path was also analysed. A final prototype was designed and printed according to optimised printing settings and maximum allowable resistances for each line and considering different geometries and printing strategies to reduce cross-contamination among paths. Findings For the Black Magic 3D conductive filament, the printing speed and layer height played a significant role regarding resistivity, while the printing temperature was not very important. The infill pattern of the conductive paths had to be aligned with the expected current path, while using air gaps between two adjacent paths resulted in the best approach to reducing cross-contamination. Moreover, the cross-section size of
Revista:
DYNA
ISSN:
0012-7361
Año:
2019
Vol.:
94
N°:
2
Págs.:
221 - 225
Additive Manufacturing devices or 3D printers allow the possibility of creating almost anything. One of the most promising fields of application are wearable devices, which can be directly printed on textiles. This paper aims to study adhesion forces and warping effects when depositing a polymer onto a textile with a low-cost extrusion 3D printer. To achieve this, two different polymers (PLA and Filaflex) and six of the most common textile materials were selected. L-shaped specimens were printed by combining the two polymers and the six textiles. Most of the common printing settings were fixed for both materials, while the layer quality was 0.1 mm and 0.2 mm. Once printed, they were inspected with a Coordinate Measuring Machine and the deformation of each specimen was quantified by calculating their maximum and minimum displacements. Afterwards, each specimen was axially tested to evaluate the adhesion forces between the polymer and the textile. In terms of warping, flexible filament showed the lowest values independent of printing quality (0.56 mm and 0.3 mm) relative to the rigid filament (0.73 mm and 0.8 mm). In terms of adhesion, the combination of a porous textile and a flexible filament got the highest values, regardless of the layer height selected. The conclusion of this study is that polymer textile deposition can be a real manufacturing strategy that should be considered when thinking about the design of a wearable device to be worn on the body.
Autores:
Zabaleta, J. (Autor de correspondencia); Aguinagalde, B. ; Lopez, I. ; et al.
Revista:
MEDICAL DEVICES
ISSN:
1179-1470
Año:
2019
Vol.:
12
Págs.:
143 - 149
Introduction: In recent years, the use of 3D printing in medicine has grown exponentially, but the use of 3D technology has not been equally adopted by the different medical specialties. Published 3D printing activity in general thoracic surgery is scarce and has been mostly limited to case reports. The aim of this report was to reflect on the results and lessons learned from a newly created multidisciplinary and multicenter 3D unit of the Spanish Society of Thoracic Surgery (SECT). Methods: This is a pilot study to determine the feasibility and usefulness of printing 3D models for patients with thoracic malignancy or airway complications, based on real data. We designed a point-of-care 3D printing workflow involving thoracic surgeons, radiologists with experience in intrathoracic pathology, and engineers with experience in additive manufacturing. Results: In the first year of operation we generated 26 three-dimensional models out of 27 cases received (96.3%). In 9 cases a virtual model was sufficient for optimal patient handling, while in 17 cases a 3D model was printed. Per pathology, cases were classified as airway stenosis after lung transplantation (7 cases, 25.9%), tracheal pathology (7 cases, 25.9%), chest tumors (6 cases, 22.2%) carcinoid tumors (4 cases, 14.8%), mediastinal tumors (2 cases, 7.4%) and Pancoast tumors (one case, 3.7%). Conclusion: A multidisciplinary 3D laboratory is feasible in a hospital setting, and working as a multicenter group increases the number of cases and diversity of pathologies thus providing further opportunity to study the benefits of the 3D printing technology in general thoracic surgery.
Revista:
PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART P-JOURNAL OF SPORTS ENGINEERING AND TECHNOLOGY
ISSN:
1754-3371
Año:
2019
Vol.:
233
N°:
1
Págs.:
160 - 169
Shin pads are part of the mandatory equipment footballers must wear so as to prevent lesions. Most players wear commercially available shin pads made from a variety of common materials (polypropylene or polyethylene) and high-resistance materials (glass fibre, carbon fibre or Kevlar) using traditional manufacturing techniques. Additive manufacturing was used years ago to deliver customised rigid shin pads, but they did not offer any significant advantage in terms of materials or design compared to traditional shin pads. This project analyses a novel approach to the design and manufacture of shin pads for football players that combines existing digitisation tools, lattice structures and a multi-material additive manufacturing device. A total of 24 different additive manufacturing geometries were evaluated using a customised rig where a 1-kg impactor was released from several heights (100-400 mm). The impact acceleration, the transmitted force to the leg and penetration were calculated. Results were compared against two commercially available shin pads. Results show that two of the additive manufacturing specimens tested at the highest drop height had lower impact accelerations than commercial shin pads. They had an acceleration reduction between 42% and 68% with respect to the commercial shin pads. Regarding the penetration, the improvement achieved with additive manufacturing specimens ranged from 13% to 32%, while the attenuation and the contact times were similar.
Revista:
DYNA
ISSN:
0012-7361
Año:
2015
Vol.:
90
N°:
6
Págs.:
621 - 627
Additive Manufacturing (AM), commonly called 3D printing, is the process of making objects layer upon layer from 3D model data in order to test design prototypes (called Rapid Prototyping), to obtain production tools (Rapid Tooling) or to build and then use that prototype as a final part in the final product (Direct Manufacturing). This paper aims to show new applications of the Direct Digital Manufacturing philosophy for sports and medical sciences. Particularly, the aim of the study is to present three case-studies that take advantage of AM so as to enable practitioners and professional players to manufacture customised 1) face masks to protect the face during sports or everyday activities, 2) foot insoles to treat foot problems and 3) shin pads to be worn by football players and shield them from shin injuries. In every case study, prior to fabrication, anthropometric features of volunteer patients were captured by a low-cost 3D scanner and a user-friendly semi-automatic modelling procedure was developed with Rhinoceros and Grasshopper in order to model and customise several features of the three products. The resulting virtual designs of the three products were manufactured with the help of four different AM devices while design workflow and the suitability of the physical prototypes were evaluated against volunteers and practitioners. Feedback results from practitioners and volunteers were satisfactory enough in order to consider the design tools provided as a good starting point for future developments. Further work is still necessary in terms of improvement to the design algorithm, inclusion of new materials and test procedures to verify the physical prototypes to the final user requirements. Nevertheless, this work confirmed that the combination of existing tools of three-dimensional digitisation, user-friendly semi-automatic algorithm within a Computer Aided Design (CAD) and Additive Manufacturing can lead to a technologically feasible and cost-effective solution to improve the traditional design and manufacturing process of customised orthotic and protective devices for sports and medical sciences.
Revista:
IEEE TRANSACTIONS ON LEARNING TECHNOLOGIES
ISSN:
1939-1382
Año:
2014
Vol.:
7
N°:
4
Págs.:
304 - 318
The combination of virtual reality interactive systems and educational technologies have been used in the training of procedural tasks, but there is a lack of research with regard to providing specific assistance for acquiring motor skills. In this paper we present a novel approach to evaluating motor skills with an interactive intelligent learning system based on the ULISES framework. We describe the implementation of the different layers that ULISES is composed of in order to generate a diagnosis of trainees' motor skills. This diagnostic process takes into account the following characteristics of movement: coordination, poses, movement trajectories and the procedure followed in a sequence of movements. In order to validate our work we generated a model for the diagnosis of tennis-related motor skills and we conducted an experiment in which we interpreted and diagnosed tennis serves of several subjects and which shows promising results.
Revista:
PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART B-JOURNAL OF ENGINEERING MANUFACTURE
ISSN:
0954-4054
Año:
2014
Vol.:
228
N°:
12
Págs.:
1664 - 1675
Design and manufacturing engineers are not fully aware of the different possibilities that PolyJet technology offers. The goal of this article is to provide the design and manufacturing engineers with greater knowledge about the final properties of parts printed with PolyJet rapid prototyping technology. This knowledge includes the effect of printing orientation and post-processing on the mechanical and surface properties of printed parts. Eighteen different samples considered all the possible printing orientations and the surface finishing treatments recommended by the manufacturer. These finishing properties include part printing using the matte/glossy option and removal of the support material using water pressure and/or a caustic soda bath. Tensile tests and surface roughness measurements were analysed for the printed samples using the statistical design of experiments in order to determinate the influence of the printing orientation and finishing properties on the results. These tests showed that the part orientation has a significant effect on elastic modulus and fracture stress while there is no statistical significance on ultimate tensile strength. With regard to the finish, none of the tensile test outputs showed significant differences. In terms of roughness, the analysis of variance indicated that position and finish presented statistically significant differences between the means of the three roughness directions. From all these experiences, it is possible to conclude that the glossy finish and the xy printing direction worked very well regarding roughness, whereas the critical load direction of the part should be placed along the x-axis when printing.
Revista:
COMPUTER-AIDED CIVIL AND INFRASTRUCTURE ENGINEERING
ISSN:
1093-9687
Año:
2013
Vol.:
28
N°:
6
Págs.:
465 - 480
Simulators provide significant advantages in training operators of concrete spraying machinery, such as economic savings, the practical absence of safety risks, and environmental and educational benefits. The main challenge in developing a real-time training simulator for concrete spraying machinery lies in the modeling of shotcrete application. This article presents a novel method that models and simulates in real time the three main factors influencing shotcrete sprayability: adhesion, cohesion, and rebound. Furthermore, thanks to the addition of an obstacle model, the method makes it possible to spray onto additional supporting elements, which is a typical shotcrete application. The proposed method considers a wet-mix thick flow spraying process and is based on experiments that were run with a real concrete spraying machine and complemented by expert advice. The method was developed and evaluated using a user-centered methodology, resulting in realistic shotcrete application modeling that meets the needs for training concrete spraying machinery operators.
Autores:
Borro, D.; Servan-Blanco, J.; Cordero-Valle, J.M.; et al.
Revista:
DYNA
ISSN:
0012-7361
Año:
2011
Vol.:
86
N°:
3
Págs.:
328 - 335
Maintenance operations have a great impact on the safety and life expectancy of any product. This is especially true for certain applications within the aerospace industry, which must pass rigorous security checking procedures. Wearable helping systems can help to reduce costs and working time by guiding workers in some specific and difficult tasks. The purpose of this work is developing a handless and wearable guided system that supports and helps workers in assembly and verification tasks within the aeronautic field. The worker is able to request information for the specific task in a non invasive way and also ask the Team Leader for real time technical support and assistance. The system developed has been tested in an aeronautic company (Airbus Military) and its implementation in specific assembly tasks assessed. It was found that the proposed system can help workers to make their tasks faster, more accurate and more secure.